scholarly journals How Cinchona Alkaloid-Derived Primary Amines Control Asymmetric Electrophilic Fluorination of Cyclic Ketones

2014 ◽  
Vol 136 (27) ◽  
pp. 9556-9559 ◽  
Author(s):  
Yu-hong Lam ◽  
K. N. Houk
Keyword(s):  
Cinchona Alkaloid ◽  
Primary Amines ◽  
Cyclic Ketones ◽  
Electrophilic Fluorination

scholarly journals Controlling the stereochemistry in 2-oxo-aldehyde-derived Ugi adducts through the cinchona alkaloid-promoted electrophilic fluorination

2020 ◽  
Vol 16 ◽  
pp. 1963-1973
Author(s):  
Yuqing Wang ◽  
Gaigai Wang ◽  
Anatoly A Peshkov ◽  
Ruwei Yao ◽  
Muhammad Hasan ◽  
...  
Keyword(s):  
Ugi Reaction ◽  
Enol Form ◽  
Cinchona Alkaloid ◽  
Chiral Center ◽  
Electrophilic Fluorination ◽  
New Strategy

In this report, we introduce a new strategy for controlling the stereochemistry in Ugi adducts. Instead of controlling stereochemistry directly during the Ugi reaction we have attempted to stereodefine the chiral center at the peptidyl position through the post-Ugi functionalization. In order to achieve this, we chose to study 2-oxo-aldehyde-derived Ugi adducts many of which partially or fully exist in the enol form that lacks the aforementioned chiral center. This in turn led to their increased nucleophilicity as compared to the standard Ugi adducts. As such, the stereocenter at the peptidyl position could be installed and stereodefined through the reaction with a suitable electrophile. Towards this end, we were able to deploy an asymmetric cinchona alkaloid-promoted electrophilic fluorination producing enantioenriched post-Ugi adducts fluorinated at the peptidyl position.

Enantioselective synthesis of trifluoromethyl substituted cyclohexanones via an organocatalytic cascade Michael/aldol reaction

2020 ◽  
Vol 18 (8) ◽  
pp. 1607-1611 ◽  
Author(s):  
Hongzhou Yang ◽  
Qingqing Wang ◽  
Yuan Luo ◽  
Ling Ye ◽  
Xinying Li ◽  
...  
Keyword(s):  
Aldol Reaction ◽  
Enantioselective Synthesis ◽  
Ring Closure ◽  
Cinchona Alkaloid ◽  
Primary Amines

An enantioselective Michael-initiated ring-closure process was established to construct β-CF3-cyclohexanones or β-CF3-cyclohexenones with cinchona alkaloid-based primary amines.

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